Radiobiology 3 MCQ

<p>LET decreases. (C)</p> Signup and view all the answers

<p>Infrequent or widely spaced ionizing events. (C)</p> Signup and view all the answers

<p>High LET induces significant cell damage with fewer energy deposits. (D)</p> Signup and view all the answers

<p>Low LET radiation. (D)</p> Signup and view all the answers

<p>Increased cell killing efficiency per Gray. (B)</p> Signup and view all the answers

<p>100-150 keV/μm (B)</p> Signup and view all the answers

<p>High LET radiation results in close ionization events causing more biological effects. (B)</p> Signup and view all the answers

<p>100 keV/μm (A)</p> Signup and view all the answers

<p>Peroxide (H2O2) (A)</p> Signup and view all the answers

<p>High LET radiation leads to a higher probability of DSBs. (B)</p> Signup and view all the answers

<p>Higher energy corresponds to lower LET and biological effects. (A)</p> Signup and view all the answers

<p>X-rays (D)</p> Signup and view all the answers

<p>Density of ionization events (A)</p> Signup and view all the answers

<p>They form peroxide (H2O2) under certain conditions. (C)</p> Signup and view all the answers

<p>Increased production of reactive oxygen species (D)</p> Signup and view all the answers

<p>When using high LET radiation with tightly spaced ionizing events (A)</p> Signup and view all the answers

<p>Have no mass (A)</p> Signup and view all the answers

<p>Oxygen Effect (A)</p> Signup and view all the answers

<p>Higher LET indicates less damage to biological material. (A)</p> Signup and view all the answers

<p>Mature somatic cells (C)</p> Signup and view all the answers

<p>M phase cells are more radiosensitive. (D)</p> Signup and view all the answers

<p>Radiosensitivity of normal tissues (A)</p> Signup and view all the answers

<p>Charged particles deposit energy localized along their tracks. (C)</p> Signup and view all the answers

<p>Oxygen Effect (C)</p> Signup and view all the answers

<p>Alpha particle (B)</p> Signup and view all the answers

<p>Create fast electrons (B)</p> Signup and view all the answers

<p>Mitotic death (C)</p> Signup and view all the answers

<p>HeLa Cells (A)</p> Signup and view all the answers

<p>It becomes steeper. (B)</p> Signup and view all the answers

<p>The cells no longer proliferate and form colonies. (D)</p> Signup and view all the answers

<p>It is accompanied by an additional SSB too far away for a double-strand break. (A)</p> Signup and view all the answers

<p>Alpha particles (A)</p> Signup and view all the answers

<p>It decreases. (B)</p> Signup and view all the answers

<p>Cell differentiation (D)</p> Signup and view all the answers

<p>Radiation overkill (C)</p> Signup and view all the answers

<p>In all established cell lines studied (A)</p> Signup and view all the answers

The way radiant energy is absorbed by biological material.

The process where an electron gains energy and jumps to a higher energy level.

The process where an atom or molecule loses an electron.

The energy deposited per unit length of track by a charged particle as it travels through matter.

The ability of different types of radiation to cause biological damage.

Cells in the early stages of development that are more sensitive to radiation.

Mature cells that are less sensitive to radiation than stem cells.

Tissues with high metabolic activity are more sensitive to radiation.

The modifying factors that influence the response of living tissues to radiation.

The presence of oxygen increases the damage caused by radiation.

The capacity of cells to reproduce and form colonies.

A process of programmed cell death, characterized by a series of biochemical events that lead to the cell's destruction.

A type of cell death that occurs when a cell tries to divide but fails, resulting in an abnormally large cell.

A type of cell death that occurs when a cell dies during the process of dividing.

The shape of a survival curve that represents the relationship between the radiation dose and the fraction of cells that survive.

The portion of the cell survival curve where the slope is shallow, suggesting that cells are more resistant to radiation.

The portion of the cell survival curve where the slope is steep, indicating that cells are more sensitive to radiation.

High LET radiation deposits energy densely along a short track, leading to clusters of ionization events. This can cause significant damage, such as double-strand breaks in DNA.

Low LET radiation deposits energy sparsely along a longer track. This can lead to less severe damage as ionization events are spread out.

Double-strand breaks (DSBs) are breaks in both strands of DNA, a highly damaging event that can lead to cell death or mutations.

The higher the energy of a particle, the lower its LET. This is because the particle interacts less frequently with matter.

The optimal LET for causing biological effects is around 100 keV/μm. This LET allows for significant DSBs within DNA.

The probability of causing DSBs is lower for sparsely ionizing radiation, such as X-rays, because ionization events are spread out.

The formation of hydrogen peroxide (H2O2) from the recombination of OH radicals can lead to oxidative damage in cells.

Linear energy transfer (LET) quantifies the energy deposited by ionizing radiation per unit length of its path through matter. It measures the density of ionization events along the radiation track.

Radiation with high LET deposits a significant amount of energy in a short distance, causing dense ionization and potentially more damage. Think of a thick, dense line of ionization.

Radiation with low LET deposits energy sparsely along its path, creating widely spaced ionization events. Imagine a less dense, spread-out line of ionization

As LET increases, the probability of cell death per unit dose of radiation also increases, meaning more cell killing occurs at a given dose.

The overkill effect occurs when high LET radiation (above a certain threshold) causes such extensive damage that cell death is no longer proportional to dose. Essentially, too much damage is being inflicted in a small space.

For a given type of particle (like alpha or proton), as its energy increases, its LET decreases, leading to less biological damage. Think of a faster bullet causing less damage.

Gamma rays, X-rays, and electromagnetic radiation in general typically have very low LET. They create widely spaced ionization events along their path.

Alpha particles have very high LET, leading to a dense trail of ionization along their path.

The low LET of radiation like gamma rays distributes energy more evenly throughout the cell, making the dose more uniform.

High LET radiation creates well-defined tracks of ionization that cause localized, intense damage along the path. Imagine a narrow, focused beam of energy.